Needle bed structure for warp knitting machines



H. C. NOE

June 12, 1956 NEEDLE BED STRUCTURE FOR WARP KNITTING MACHINES 3 Sheets-Sheet l INVENTOR. fiaro/ICJVoe F'i'led Nov. 25, 1952 H. C. NOE

June 12, 1956 NEEDLE BED STRUCTURE FOR WARP KNITTING MACHINES 3 SheetsSheet 2 Filed Nov. 25, 1952 INVENTOR. 1701 0!!! CMe Con/1AM ATTOBAEY June 12, 1956 H. c. NOE 2,749,730

NEEDLE BED STRUCTURE FOR WARP KNITTING MACHINES Filed Nov. 25, 1952 3 Sheets-Sheet 3 INVENTOR. Hero/cl C.Noe

ATTORNEY nited rates Patent NEEDLE BED STRUCTURE FOR WARP KNITTING MACHINES Harold C. Noe, Upper Montclair, N. 1., assignor to Kidde Manufacturing Co., Inc., Bloomfield, N. J., a corporation of Delaware Application November 25, 1952, Serial No. 322,435

Claims. (Cl. 66--86) This invention relates to warp knitting machines, such as Raschel machines, and, more particularly, to an improved needle bed structure for such machines.

Heretofore, one of the inherent disadvantages of warp knitting machines was that such machines could not knit fine stitches closely adjacent each other in the warp chains, because, in attempting to knit such stitches, tighter loops were formed on the needles and the fabric take-up was decreased, whereupon the tight stitches could load up at the relatively wide hook end of the needles and could not be fully cast off. Thereafter, as the needles, carrying the stitches which had not been cast off, moved upwardly, the take-up tension caused the warp thread to break.

In order to remedy this disadvantage, two expedients were attempted. First, the stroke of the needles was lengthened, allowing them to travel further downward between the tricks of the needle bed, and at the same time, the take-up tension in the fabric was increased to remove the stitches from the needles. The results attained by this method were not satisfactory because the increased take-up tension made it impossible to knit rows of stitches closely adjacent each other in the warp chain. Second, the needle bar operating cam was formed so that the needles, after completing the down stroke, traveled a portion of the length of the up stroke, stopped, and then returned to their lower limit of travel before rising to the lapping position. This method of operation provided suitable casting off of the stitche from the needles but provided an extra, time consuming operation.

Accordingly, an object of the present invention is to provide a simple, economical and practical needle bed structure which overcomes the foregoing difficulties.

Another object is to provide such structure which assists in removing stitches from the needles without additional needle movement.

Another object is to provide such structure which enables the knitting machine to be operated at higher speeds than heretofore possible to thereby increase the efliciency and output of such machines.

Another object is to enable such machines to produce knitted fabrics at such speeds having stitches closely adjacent each other in the warp chains.

A further object is to provide a knockover edge which is not subject to excessive wear and which is readily replaceable, in the event of damage, without the necessity of replacing the entire needle bed.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiments about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In accordance with the invention, the foregoing objects are accomplished by providing a needle bed structure having means such as a wire, band or the like, adjacent the stitch separating edges thereof extending lengthwise of the needle bed and providing a continuous knockover surface adjacent the stitch separating edges over which the stitches are adapted to pass and being movable with respect to the needle bed structure so as to assist in clearing stitches.

In the accompanying drawings, forming a part of the specification Fig. 1 is a fragmentary perspective view of one form of a needle bed structure in accordance with the invention.

Fig. 2 is a schematic view of the needle bed structure shown in Fig. 1 together with cooperating knitting elements including a needle, a sinker and a yarn guide illustrating their positions in one phase of the knitting cycle.

Figs. 3 to 10 are views similar to Fig. 2 illustrating the same elements in sequential positions of the knitting cycle.

Fig. 11 is a fragmentary perspective view illustrating another form of needle bed structure in accordance with the invention.

Fig. 12 is a schematic view of the needle bed structure shown in Fig. 11 together with cooperating knitting elements including a needle, a sinker and a yarn guide, illustrating their positions in one phase of the knitting cycle.

Figs. 13 to 16 are view similar to Fig. 12 illustrating the same elements in sequential positions of the knitting cycle.

Referring to the drawings in detail and more particularly to Fig. 1 thereof, there is shown a portion of a needle bed structure, trick plate 10 or the like, which essentially comprises a body portion 11 adapted for securement to the frame of a Raschel type knitting machine, and a series of longitudinally spaced trick blades 12 parallel to each other having a stitch separating edge 14 at the upper end and providing slots or grooves for receiving the needles.

The edges 14 are each formed with an arcuate recess 15 at the front corner, and a wire or rod 16 over which the knitted stitches in the warp chains pass is partially received by the recesses to mount the same for movement with respect to the trick blades 12. This wire extends along the entire length of the needle bed structure and provides a continuous knockover surface 17 adjacent the stitch separating edges 14 for assisting clearing of the stitches in the manner about to be described. Preferably, the surface 17 is slightly above the edges 14. The wire may terminate at the ends of the needle bed structure, and may be retained in the recesses merely by the warp chains passing over the surface 17 or each end of the wire may extend beyond the needle bed structure and may be journaled for rotation in a suitable bearing 19 on the frame of the machine.

In Figs. 2 to 10, one set of knitting elements of a Raschel type knitting machine is partially shown in se quential positions, with respect to the needle bed structure just described, throughout the knitting cycle of the machine. While the machine actually comprises a great number of such sets of elements, depending on the width of the bed structure and the gauge of the needles, illustration and description of one of these sets will be sufficient for the purpose of understanding the present invention because their construction and operation are identical. These elements include a latch needle 21 having a hook 22 and a latch 24, a sinker blade 25 having a toe portion 26 and a weft receiving recess 27 for use in weft knitting and a yarn guide 29.

In Fig. 2, a strand of yarn or warp thread 36 is shown passing through the guide 29, and extending through a stitch 31 formed about the lower portion of the needle shank, this stitch having been knitted into a warp chain of fabric 32 which passes over the wire 16 to the take-up roll (not shown) under suitable tension. The needle 21 is in its uppermost position with its latch 24 down, the sinker 25 is in its innermost position with respect to the needle to hold down the stitch 31, and the guide 29 is in front of the needle.

Figs. 3 and 4 illustrate the conventional lapping of the yarn about the needle while the sinker is being withdrawn to prevent the same from subsequently interfering with the needle. In Fig. 3, the needle is still in its uppermost position and the guide has been rocked inback of the needle and to one side thereof, and, in Fig. 4, the needle begins to descend and the guide has been rocked in front of the needle and to the other side thereof, whereby the yarn 30 encircles the needle between the hook 22 and the latch 24 to cast a loop 33 on the needle.

In Fig. 5, the needle continues to descend and the stitch 31 about the lower portion of the needle commences to close the latch 24, and in Fig. 6, further downward movement of the needle has caused the stitch to close the latch and the hook 22' is about to engage the loop 33.

In Fig. 7, still further downward movement of the needle has caused the stitch 31 to pass over the tip of the latch and about to be cast 011? the needle and has caused the hook to engage the bend of the loop 33.

As the needle approcaches its lowermost position as shown in Fig. 8, the stitch 31 is cast off the needle and the hook draws the loop 33 through the stitch 31 to form a new loop 31a which later becomes a stitch knitted to the stitch 31. At this phase of the knitting cycle, the take-up tension causes the fabric 32 to be drawn away from the needle path because the stitch 31 is no longer engaged and supported by the needle.

The unbalancing of this force, with respect to the tension in the yarn 30, together with the fact that the coeflicient of friction between the wire 16 and the fabric 32 is greater than that between the wire and recess 15, causes the wire to act as a roller bearing and to rotate in the recess in a clockwise direction, as viewed. Such rotation is sufficient to assist the casting off of the stitch 31 from the needle.

As the needle 21 reaches its lowermost position, as shown in Fig. 9, the new loop 31a is formed around the book 22 thereof, thereby increasing the tension in the yarn or warp thread 30 so that it again balances the fabric take-up tension, whereupon the wire 16 immediately ceases to rotate and the stitch 31 is retained momentarily on the knockover edge 17 while the increased yarn tension causes the same to be tightened and establish a smaller stitch.

Also, by tightening the stitch, it is possible to knit a finer fabric having closely adjacent stitches in the warp chains thereof.

As shown in Fig. 10, the needle 21 has started its upward stroke in the knitting cycle thereby causing the tension in the yarn 30 to be relaxed and allowing the fabric take-up to rotate the wire 16 again in the manner just described. This second rotation assists the tightened stitch 31 to pass over the knockover edge 17 of wire 16 with less frictional resistance thereto.

As shown in Fig. 10, the sinker has been moved forward again towards its innermost position to engage the new stitch 31a and hold it down while the needle ascends to its uppermost position as shown in Fig. 2.

While the latch 24 is shown open in Figs. 8 to 10, probably it is pulled down by the new'stitch 31a as the needle ascends from the position shown in Fig. to that shown in Fig. 2, the sinker serving to hold the stitch against upward movement while the latter opens the latch.

It will of course be understood that adjacent warp chains will be knitted together in the conventional manner during the operation of the machine.

In Fig. 11, there is shown a portion of another form of needle bed structure, trick plate 35 or the like, which comprises essentially a body portion 36 adapted for securement to the frame ofthe knitting, machine and a series of longitudinally spaced trick blades 37 parallel to each other to provide slots or grooves for receiving the needles. The trick plates have a stitch separating edge 39 at the upper end and have a front edge 40.

The body portion 36 has an upper extension 41, a lower extension 42 and an enlarged shoulder portion 44 projecting outwardly from the front side thereof between extensions 41 and 42. The upper extension 41 has a front wall 45 which is inclined upwardly and forwardly with respect to the plane of the lower extension 42 and which is parallel with the front edges 40 of the trick blades. The upper surface of the shoulder portion 44 is curved downwardly and inwardly so as to meet the side wall 45 at an acute angle thereby forming a recess 47 which extends lengthwise of the needle bed;

A band or strip 49, preferably formed of spring steel or other suitable material, extends lengthwise along the needle bed and has its lower edge 51 loosely mounted in the recess 47 for pivotal movement or the like. The upper edge 52 of the band 49 provides a continuous knockover edge or surface adjacent the stitch separating edges 39 of blades 37. Preferably, the edge 52 is slightly above the edges 39. The back side of the band is adapted to rest against the front wall 45 of the body portion 36. The band may be retained in the recess 47 merely by the warp chains passing over the surface 52, or the ends thereof may have a wire 54 attached thereto which is connected to the frame of the machine to prevent legnthwise creeping.

In Figs. 12 to 16, a set of knitting elements such as hereinbefore described is partially shown in certain sequential positions with the needle bed structure of Fig. 11 during which the band 49 functions in effect like the wire 16. The lapping of the thread or yarn onto the needle in the conventional manner and the complete downward stroke of the needles are not shown, so that the positions of the elements in Figs. 12, 13, 14, 15 and 16 correspond substantially to such positions in Figs. 7, 8, 9, 10 and 2, respectively.

In Fig. 12, the needle 21 has been moved downwardly sufficiently to cause the stitch 31 to pass over the tip of the latch 24 but the stitch is still supported by the needle whereby take-up pull on the fabric is resisted and the back side of the band rests against the front wall 45 or in its normal position.

In Fig. 13, the stitch 31 has been cast off the downwardly moving needle 21 and a new stitch 31a is being formed. At this point of the knitting cycle, the take-up tension usually is greater than the yarn tension and its outward and downward components cause the knockover edge of the band to move with the fabric away from the stitch separating edges 39 until the stitch 31 is removed from the needle path, if the fabric does not slide over the edge. When both the fabric and the knockover edge move together, there is no frictional resistance therebetween to hinder the fabric movement.

As the needle continues downward, the new stitch 31a is drawn through the cast-off stitch 31, as shown in Fig. 14, and the angle between the band and the stitch 31a decreases until its relation to the angle between the takeup fabric and the band is such that the take-up tension forces the knockover edge of the band to slide under the fabric until it reaches its normal position adjacent the stitch separating edges 39.

When, the needle starts to ascend, thereby increasing the angle between the new stitch 31a andthe band and allowing the new stitch to slacken, the band may again be moved away from the stitch clearing edges 39 as shown in Fig. 15; but, when the needle has reached the position actually shown in Fig. 15, the band is just about to return to its normal position.

In Fig. 16, the needle 21 has traveled upwardly so that the slack in stitch 31a is taken up to again tension the yarn and cause the band 49 to return to its normal position by sliding beneath the fabric and the stitch 31 so that the stitch moves, with respect to the band, to the fabric side of the knockover surface 17.

In some instances, under c :rtain conditions of operation, the upper zone of the band 49 may flex to produce the same effect as is attained by pivoting the band. Thus instead of relying on pivotal or similar movement of the band, the lower edge of the band may be fixed and the upper zone of the band may be flexible to accomplish the purpose of the invention.

It will be understood that the operation of the wire 16 or band 49 depends upon the relative tension forces in the warp or yarn and the take-up fabric, and that the functioning of the wire or band can be controlled to cause tighter or looser stitches to be knitted by adjusting the magnitude or direction of such tension forces.

While the present invention has been described in connection with needle bed structure of a new and improved design which is the subject matter of my Letters Patent of the United States, issued today on application, Serial No. 322,434, filed November 25, 1952, it will be appreciat'ed that existing needle beds consisting of a plate having trick blades machined therein may be modified to provide a recess for rotatably receiving a wire 16 or to provide a notch for pivotally supporting a band 49. It will therefore be understood, that the term needle bed structure is used herein in a generic sense and is intended to include all forms of needle beds or trick plates utilized in connection with warp knitting machines of the Raschel type.

From the foregoing description, it will be seen that the present invention provides an improved needle bed structure for Warp knitting machines which is simple in construction, economical to manufacture and practical in operation, and which enables finer fabrics to be produced at higher speeds than have been possible heretofore.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. Needle bed structure of the class described comprising a plurality of spaced blade means providing open ended needle slots and each having side edges and a stitch separating edge at the open end of the needle slots, and an element structurally free and disconnected from the needle bed structure and adjacent the stitch separating edges of said blade means and extending lengthwise along the needle bed structure to provide a continuous surface adjacent said edges over which the stitches are adapted to pass, said element being mounted for movement exteriorly of the said edges of said blade means in the functioning of the bed structure.

2. Needle bed structure of the class described having recess means adjacent the stitch separating edges thereof and extending lengthwise thereof, and a member rotatably supported by said recess means providing a continuous surface adjacent said edges over which the stitches are adapted to pass.

3. Needle bed structure of the class described comprising a plurality of spaced blades, an arcuate recess in each of said blades adjacent the stitch separating edges thereof, and a wire rotatably mounted in said recesses and extending lengthwise along the needle bed structure to provide a continuous surface adjacent said edges over which the stitches are adapted to pass.

4. Needle bed structure according to claim 3, wherein means are provided for retaining said wire in said recess means.

5. Needle bed structure according to claim 4, wherein said wire retaining means constitute bearing means for rotatably mounting the ends of said wire.

6. Needle bed structure of the class described having a lengthwise extending recess below the stitch separating edges, and a band having one edge in said recess and extending lengthwise along the needle bed structure and having its other edge adjacent said stitch separating edges to provide a continuous surface over which the stitches are adapted to pass, said surface being movable with re spect to said stitch separating edges.

7. Needle bed structure according to claim 6, wherein said recess is in the form of a notch and means for pivotally retaining the lower edge of said band.

8. Needle, bed structure according to claim 6, wherein the upper edge of said band is adjacently above said stitch separating edges.

9. Needle bed structure according to claim 6, wherein the upper zone of said band is flexible to facilitate movement of said surface with respect to said stitch separating edges.

10. A needle bed for warp knitting machines comprising bed structure having open ended needle slots, side edges and a stitch separating edge at the open end of each of the needle slots, and an element adjacent said stitch separating edges of said bed structure and extending lengthwise along said bed structure and structurally free and disconnected from said bed structure to provide a continuous surface adjacent the portions of said stitch separating edges over which stitches are adapted to pass, said element being mounted for movement exteriorly of said edges in the functioning of the needle bed.

References Cited in the file of this patent UNITED STATES PATENTS 1,210,106 Schwartz Dec. 26, 1916 1,436,529 Preston Nov. 21, 1922 2,014,529 Kinsella et a1. Sept. 17, 1935 2,155,145 Morton et a1 Apr. 18, 1939 2,259,655 Morton Oct. 21, 1941 2,428,448 Broberg Oct. 7, 1947 2,461,550 Lambach Feb. 15, 1949 2,504,316 Fontaine Apr. 18, 1950 2,682,163 Staff et a1 June 29, 1954 

